There is no scientific consensus that 90% of your mind begins to imagine stuff you'd like to happen before sleeping. The process of falling asleep and the content of thoughts during that period can vary significantly from person to person and may be influenced by various factors, such as one's emotional state, daily experiences, and overall mental processes.
During the transition from wakefulness to sleep, people may experience a range of thoughts, emotions, and mental images. Some individuals might engage in daydreaming or imagine positive scenarios, while others may experience more random or neutral thoughts. The content of thoughts before sleep can be influenced by various factors, including stress levels, recent experiences, and personal preferences.
Dreams are more prevalent during rapid eye movement (REM) sleep, which is a stage of sleep that occurs periodically throughout the night. Dreams can involve a wide array of experiences, emotions, and narratives, and they are not limited to imagining things you'd like to happen. Dreams can be vivid, fantastical, and sometimes even unsettling or nonsensical.
It's important to remember that sleep and dreams are complex phenomena that continue to be studied by psychologists and neuroscientists. While there are general patterns and common experiences, individual variations are also quite significant. If you have specific concerns about your sleep or dream patterns, it's best to consult a healthcare professional or sleep specialist who can provide personalized guidance and support.